In FY91, DTS developed an urgent need to evaluate the safety of stored packed red cells (prbc's) with regard to transmission of bacterial and viral agents. Concern about the risk of sepsis and death due to transfusion of yersinia-contaminated prbc's prompted the Blood Products Advisory Committee to recommend reducing the storage time for packed cells. Available data suggested that deaths associated with yersinia contaminated units tend to increase with the time cells are stored at 2- 6 degrees C. In contrast, evidence suggests that the risk of transmission of HIV by transfusion of contaminated units decreases with longer blood storage time. A novel infectivity assay developed under project Z01 BG 0631-02(LR) was used to experimentally determine the survival of cell-free and cell- associated HIV-1 virus in prbc's stored at 2-6 degrees C in commonly used anticoagulants, CPDA and ADSOL. Donor prbc's collected in ADSOL or CPDA were spiked with cell-free and cell-associated HIV-1 virus and stored in collection bags at 2-6 degrees C. Samples were drawn and exponential decline of infectious HIV-1 with time was determined. In duplicate experiments, the half-life of infectious HIV-1 was shown to be 3.0 days when stored in prbc's in CPDA and 7.5 and 4.2 days when stored in prbc's in ADSOL. The data was presented at the annual meeting of the American Association of Blood Banks in Baltimore, November 9-14, l991.